This invention relates generally to gas turbine engines, and more specifically to a turbofan engine assembly that includes a counter-rotating booster compressor.
At least some known turbofan engine assemblies include a fan assembly, a core gas turbine engine, and a low-pressure or power turbine. The core gas turbine engine includes at least one compressor, a combustor, and a high-pressure turbine that are coupled together in a serial flow relationship. Moreover, at least one known turbofan engine assembly includes a booster that is disposed between the fan assembly and the core gas turbine engine.
To increase engine efficiency, at least one known turbofan engine assembly includes a counter-rotating low-pressure turbine that is coupled to a counter-rotating fan assembly. More specifically, to assemble a turbofan engine assembly that includes a counter-rotating low-pressure turbine, an outer rotating spool, a rotating frame, a mid-turbine frame, and two concentric shafts, are installed within the turbofan engine assembly to facilitate supporting the counter-rotating low-pressure turbine. However, while the use of a counter-rotating low-pressure turbine increases the overall engine efficiency, the counter-rotating low-pressure turbine also increases the overall stage count, thus increasing the overall weight, design complexity, and/or manufacturing costs of such an engine are increased.